1 files changed, 4 insertions, 1 deletions
diff --git a/debug.c b/debug.c
index 4eaae0d978..a5ae6a7467 100644
--- a/debug.c
+++ b/debug.c
@@ -140,6 +140,9 @@ ruby_debug_breakpoint(void)
 static void
 set_debug_option(const char *str, int len, void *arg)
 {
+#if defined _WIN32 && RUBY_MSVCRT_VERSION >= 80
+    extern int ruby_w32_rtc_error;
+#endif
 #define SET_WHEN(name, var, val) do {	    \
 	if (len == sizeof(name) - 1 &&	    \
 	    strncmp(str, (name), len) == 0) { \
@@ -149,7 +152,7 @@ set_debug_option(const char *str, int len, void *arg)
     } while (0)
     SET_WHEN("gc_stress", *ruby_initial_gc_stress_ptr, Qtrue);
     SET_WHEN("core", ruby_enable_coredump, 1);
-#if defined _WIN32 && defined _MSC_VER && _MSC_VER >= 1400
+#if defined _WIN32 && RUBY_MSVCRT_VERSION >= 80
     SET_WHEN("rtc_error", ruby_w32_rtc_error, 1);
 #endif
     fprintf(stderr, "unexpected debug option: %.*s\n", len, str);